A variety of faucet-mounted water filters such as those described in patents U.S. Pat. Nos. 4,172,796; 4,680,116; 4,686,037 and 4,770,768 have been previously described. Filters of this type have a number of shortcomings. They are complicated in construction, require numerous parts, and are consequently expensive to produce. The unfiltered water is forced to make a circuitous route through the filter housing which requires internal ductwork, usually to direct the water to the top or bottom of the filter. This complicates the construction and requires intricate molds. For example, patents U.S. Pat. Nos. 4,686,037 and 4,770,768 both require 27 separate parts. Moreover, in these patents, the filter is spaced a substantial distance to one side of the faucet by means of a horizontally disposed base portion which is enclosed within an upper and lower cover primarily for aesthetic purposes. As a result, the device is not only complicated but, because the filter is mounted a substantial distance to one side of the faucet, it occupies more space around the end of the faucet and tends to be in the way of the user. Moreover, the filter cartridges contain a granular filter material through which channels can form so that a substantial fraction of the water passes through unfiltered. Complicated ductwork is also required to direct water through an inlet surface at the bottom of the cartridge and to collect it from an outlet surface at the top of the cartridge. Another problem results from the use of a rotary diverter valve which stays in the "on" or "filter" position once set there. The valve body also extends horizontally at right angles to the downward direction of the water flowing out of the faucet. This tends to displace the filter housing further from the center axis of the water faucet. Another shortcoming is the inability to remove heavy metals and the lack of a way to pass water first through a carbon filter and then through a second filter medium.
In view of these and other deficiencies of the prior art, it is a general objective to provide an improved faucet-mounted water filter which is highly efficient in its water filtration capabilities, is compact and rugged in construction and has been reduced in cost through the elimination of a number of parts previously employed. It is a further object to reduce the amount of space occupied around the end of the faucet by having the filter and associated structure positioned close to the end of the water faucet. A further object is to both filter the water and remove chemical impurities through absorption, to lessen the possibility of channeling within the filter so that the filter lasts longer before requiring replacement. It is also an object to provide a faucet-mounted water filter that is easy to install and maintain. It is another object to provide a filter having an upright tubular water diverter with a filter housing connected to the diverter by means of a duct which projects from the wall of the diverter to the filter housing. A further object is to provide a way of having the diverter valve indicate its setting, "filter" or "nonfilter", and to return automatically to the nonfilter position when the water is turned off. Yet another object is to provide a prefilter formed from paper or the like and a carbon block filter to receive water that has passed through the prefilter.
These and other more detailed and specific objects of the invention will be better understood by reference to the following detailed description and figures which illustrate by way of example but a few of the various forms of the invention within the scope of the appended claims.